I sometimes wake up with a wet, sticky spot on my underwear or pajama pants. It's not urine, so what is it?
-- MR

Chances are that you had a "wet dream" - something that can be embarrassing and confusing to teen guys, but it's completely normal. A wet dream is also known as a nocturnal emission. Nocturnal means "at night" and emission means "discharge." This makes sense because a wet dream is when semen (the fluid containing sperm) is discharged from the penis during ejaculation while a guy is asleep. Usually wet dreams occur during a dream that has sexual images.

Wet dreams begin during puberty when the body starts making more testosterone, the major male hormone. Although some guys may feel embarrassed or even guilty about having wet dreams, they can't be controlled voluntarily (that is, you can't stop them from happening) - and almost all guys normally experience them at some time during puberty and even as adults.

For more information, check out these articles:

Is It Normal to Get Erections?
Is My Penis Normal?
Male Reproductive System

Reviewed by: Steven Dowshen, MD
Date reviewed: August 2004